Complete atrioventricular block after valvular heart surgery and the timing of pacemaker implantation

Permanent Pacemaker Implantation and Long-Term Outcomes of Patients Undergoing Concomitant Mitral and Tricuspid Valve Surgery

BACKGROUND

Tricuspid valve annuloplasty (TA) during mitral valve repair (MVr) is associated with increased risk of permanent pacemaker (PPM) implantation, but the magnitude of risk and long-term clinical consequences have not been firmly established.

OBJECTIVES

This study assesses the incidence rates of PPM implantation after isolated MVr and following MVr with TA as well as the associated long-term clinical consequences of PPM implantation.

METHODS

State-mandated hospital discharge databases of New York and California were queried for patients undergoing MVr (isolated or with concomitant TA) between 2004 and 2019. Patients were stratified by whether or not they received a PPM within 90 days of index surgery. After weighting by propensity score, survival, heart failure hospitalizations (HFHs), endocarditis, stroke, and reoperation were compared between patients with or without PPM.

RESULTS

A total of 32,736 patients underwent isolated MVr (n = 28,003) or MVr + TA (n = 4,733). Annual MVr + TA volumes increased throughout the study period (P < 0.001, trend), and PPM rates decreased (P < 0.001, trend). The incidence of PPM implantation <90 days after surgery was 7.7% for MVr and 14.0% for MVr + TA. In 90-day conditional landmark-weighted analyses, PPMs were associated with reduced long-term survival among MVr (HR: 1.96; 95% CI: 1.75-2.19; P < 0.001) and MVr + TA recipients (HR: 1.65; 95% CI: 1.28-2.14; P < 0.001). In both surgical groups, PPMs were also associated with an increased risk of HFH (HR: 1.56; 95% CI: 1.27-1.90; P < 0.001) and endocarditis (HR: 1.95; 95% CI: 1.52-2.51; P < 0.001), but not with stroke or reoperation.

CONCLUSIONS

Compared to isolated MVr, adding TA to MVr was associated with a higher risk of 90-day PPM implantation. In both surgical groups, PPM implantation was associated with an increase in mortality, HFH, and endocarditis.

Long-Term Atrioventricular Block Following Valve Surgery: Electrocardiographic and Surgical Predictors

BACKGROUND

Bradyarrhythmia requiring pacemaker implantation among patients undergoing valve surgery may occur even after several years, with unclear predictors. Our aim was to investigate the incidence of pacemaker implantation at different follow-up times and identify associated predictors.

METHODS

We conducted a retrospective study evaluating 1046 consecutive patients who underwent valve surgery at the Cardiac Surgery Division of Bologna University Hospital from 2005 to 2010.

RESULTS

During 10 ± 4 years of follow-up, 11.4% of these patients required pacemaker implantation. Interventions on both atrioventricular valves independently predicted long-term pacemaker implantation (SHR 2.1, 95% CI 1.2-3.8, p = 0.014). Preoperative atrioventricular conduction disease strongly predicted long-term atrioventricular block, with right bundle branch block as the major predictor (SHR 7.0, 95% CI 3.9-12.4, p < 0.001), followed by left bundle branch block (SHR 4.9, 95% CI 2.4-10.1, p < 0.001), and left anterior fascicular block (SHR 3.9, 95% CI 1.8-8.3, p < 0.001).

CONCLUSION

Patients undergoing valvular surgery have a continuing risk of atrioventricular block late after surgery until the 12-month follow-up, which was clearly superior to the rate of atrioventricular block observed at long-term. Pre-operative atrioventricular conduction disease and combined surgery on both atrioventricular valves are strong predictors of atrioventricular block requiring pacemaker implantation.

Outcomes of leadless pacemaker implantation after cardiac surgery and transcatheter structural valve interventions

INTRODUCTION

Permanent pacing indications are common after cardiac surgery and transcatheter structural valve interventions. Leadless pacemakers (LPs) have emerged as a useful alternative to transvenous pacemakers. However, current commercially available LPs are unable to provide atrial pacing or cardiac resynchronization and relatively little is known about LP outcomes after cardiac surgery and transcatheter valve interventions.

METHODS

This retrospective study included patients who received a Micra VR (MicraTM MC1VR01) or Micra AV (MicraTM MC1AVR1) (Medtronic) leadless pacemaker following cardiac surgery or transcatheter structural valve intervention between September 2014 and September 2022. Device performance and clinical outcomes, including ventricular pacing burden, ejection fraction, and need for conversion to transvenous pacing systems, were evaluated during follow-up.

RESULTS

A total of 78 patients were included, of whom 40 received a Micra VR LP implant, and 38 received a Micra AV LP implant. The mean age of the cohort was 65.9 ± 17.9 years, and 48.1% were females. The follow-up duration for the entire cohort was 1.3 ± 1.1 years: 1.6 ± 1.3 years for the Micra VR group and 0.8 ± 0.5 years for the Micra AV group. Among the cohort, 50 patients had undergone cardiac surgery and 28 underwent transcatheter structural valve interventions. Device electrical performance was excellent during follow-up, with a small but clinically insignificant increase in ventricular pacing threshold and a slight decrease in pacing impedance. The mean right ventricle pacing (RVP) burden significantly decreased over time in the entire cohort (74.3% ± 37.2% postprocedure vs. 47.7% ± 40.6% at last follow-up, p < .001), and left ventricle ejection fraction (LVEF) showed a modest but significant downward trend during follow-up (55.0% ± 10.6% vs. 51.5% ± 11.2% p < .001). Patients with Micra VR implants had significantly reduced LVEF during follow-up (54.1% ± 11.9% vs. 48.8% ± 11.9%, p = .003), whereas LVEF appeared stable in the Micra AV group during follow-up (56.1% ± 9.0% vs. 54.6% ± 9.7%, p = .06). Six patients (7.7%) required conversion to transvenous pacing systems, four who required cardiac resynchronization for drop in LVEF with high RVP burden and two who required dual-chamber pacemakers for symptomatic sinus node dysfunction.

CONCLUSION

Leadless pacemakers provide a useful alternative to transvenous pacemakers in appropriately selected patients after cardiac surgery and transcatheter structural valve interventions. Device performance is excellent over medium-term follow-up. However, a significant minority of patients require conversion to transvenous pacing systems for cardiac resynchronization or atrial pacing support, demonstrating the need for close electrophysiologic follow-up in this cohort.

How robust are recommended waiting times to pacing after cardiac surgery that are derived from observational data?

AIMS

For bradycardic patients after cardiac surgery, it is unknown how long to wait before implanting a permanent pacemaker (PPM). Current recommendations vary and are based on observational studies. This study aims to examine why this variation may exist.

METHODS AND RESULTS

We conducted first a study of patients in our institution and second a systematic review of studies examining conduction disturbance and pacing after cardiac surgery. Of 5849 operations over a 6-year period, 103 (1.8%) patients required PPM implantation. Only pacing dependence at implant and time from surgery to implant were associated with 30-day pacing dependence. The only predictor of regression of pacing dependence was time from surgery to implant. We then applied the conventional procedure of receiver operating characteristic (ROC) analysis, seeking an optimal time point for decision-making. This suggested the optimal waiting time was 12.5 days for predicting pacing dependence at 30 days for all patients (area under the ROC curve (AUC) 0.620, P = 0.031) and for predicting regression of pacing dependence in patients who were pacing-dependent at implant (AUC 0.769, P < 0.001). However, our systematic review showed that recommended optimal decision-making time points were strongly correlated with the average implant time point of those individual studies (R = 0.96, P < 0.001). We further conducted modelling which revealed that in any such study, the ROC method is strongly biased to indicate a value near to the median time to implant as optimal.

CONCLUSION

When commonly used automated statistical methods are applied to observational data with the aim of defining the optimal time to pacing after cardiac surgery, the suggested answer is likely to be similar to the average time to pacing in that cohort.

Simultaneous Tricuspid and Pulmonic Valve Replacement Due to Infective Endocarditis

Right-sided valvular infective endocarditis (RSIE) is often associated with intravenous (IV) drug abuse and typically involves the tricuspid valve. The involvement of both the tricuspid and pulmonic valves is a rare entity. A 39-year-old woman presented with fever, dyspnea on exertion, and chest pain. She was subsequently found to have infectious endocarditis (IE) with the involvement of both the tricuspid and pulmonic valves. Simultaneous tricuspid and pulmonic valvular repair with bioprosthetic valves were performed with bovine pericardium to reconstruct the anterior surface of the pulmonary artery. Recovery was complicated by the development of a complete atrioventricular (AV) block requiring pacemaker implantation. Following device placement, the patient also developed two episodes of ventricular tachycardia arrest likely precipitated by the device. Return of spontaneous circulation (ROSC) was achieved and no further episodes occurred once the device was exchanged with a cardiac resynchronization therapy defibrillator. The patient improved clinically and was discharged home with no further complications.

Does Pacemaker Implantation After Surgical Aortic Valve Replacement Impact Long-Term Morbidity and Mortality? A Focused Review

Permanent pacing remains a serious complication that can occur in the postoperative period of surgical aortic valve replacement. The reported incidence is variable, and there are many perioperative factors that have been linked with a greater need for permanent pacing. Permanent pacing can also be associated with late lead-related and cardiac complications that can affect late outcome. However, the degree of late dependence on pacemakers is varied, and some studies have shown that a substantial proportion of patients do not need long-term pacing. Some groups have found that permanent pacing was associated with a negative impact on long-term survival in these patients. A common finding among these studies is that the groups of patients with pacemakers had higher preoperative surgical risk and comorbidity status. This makes it difficult to establish whether permanent pacing on its own represents a risk factor for late mortality or whether it is simply a marker that reflects the higher complexity and comorbidities in this group of patients.

Predictors of permanent pacemaker insertion after mitral valve replacement: a systematic review

OBJECTIVE

As the established surgical mitral valve replacement (MVR) expands towards various contemporary techniques and access routes, the predictors and burden of procedure-related complications including the need for permanent pacemaker (PPM) implantation need to be identified.

METHODS

Digital databases were searched systematically to identify studies reporting the incidence of PPM implantation after MVR. Detailed study and patient-level baseline characteristics including the type of study, sample size, follow-up, number of post-MVR PPM implantations, age, gender, and baseline ECG abnormalities were abstracted.

RESULTS

A total of 12 studies, recruiting 37,124 patients were included in the final analysis. Overall, 2,820 (7.6%) patients required a PPM with the net rate ranging from 1.7% to 10.96%. Post-MVR atrioventricular (AV) block was the most commonly observed indication for PPM, followed by sinoatrial (SA) node dysfunction, and bradycardia. Age, male gender, pre-existing comorbid conditions, prior CABG, history of arrhythmias or using anti-arrhythmic drugs, AF ablation, and double valve replacement were predictors of PPM implantation post-MVR.

CONCLUSION

Age, male gender, comorbid conditions like diabetes and renal impairment, prior CABG, double valve replacement, and anti-arrhythmic drugs served as positive predictors of PPM implantation in patients undergoing MVR. This article is protected by copyright. All rights reserved.

Impact of early (<7 days) pacemaker implantation after cardiac surgery on long-term pacemaker dependency

OBJECTIVE

We aimed to investigate pacemaker dependency after at least 1 year in patients with early (<7 days) implantation, compared to those who received a pacemaker ≥7 days after cardiac surgery. Secondary endpoints were length of hospital stay and in-hospital complications.

METHODS

Retrospective analysis of 108 consecutive patients who received a pacemaker after cardiac surgery between 06/2012 and 06/2018. Characteristics and outcomes were compared between patients with early (<7 days) and late (≥7 days) implantation. Patients were followed up with evaluation of pacemaker dependency between April and June 2019. We identified predictors of dependency by logistic regression.

RESULTS

In total, 63.9% were men, average age 71.9 ± 11.8 years; 32 (29.6%) had early implantation, and 76 (70.4%) late implantation. After a median 3.2 years [IQR 1.9, 4.5] of follow-up, 30 patients (27.8%) had died, and there was no difference in pacemaker dependency among survivors (66.7% vs. 46.5%, early vs. late respectively, p = .15). Patients in the early group had a shorter length of stay (11.5 [9.0, 14.0] vs. 15.0 [11.5, 20] days, p = .002) and less often had new-onset atrial fibrillation (AF) post-surgery (22.7% vs. 47.8%, p = .05). The only significant predictor of dependency was aortic valve replacement surgery (OR = 4.70, 95% CI [1.36 to 16.24]).

CONCLUSION

Early implantation of a permanent pacemaker (<7 days after cardiac surgery) does not impact on the proportion of patients with long-term (>12 months) pacemaker dependency, but is associated with shorter length of stay and less frequent new-onset AF. These findings warrant prospective confirmation in randomized trials.

Perioperative management in cardiovascular surgery

Cardio-surgical patient care requires a comprehensive and multidisciplinary approach to develop strategies to improve patient safety and outcomes. In the preoperative period, prophylaxis for frequent postoperative complications, such as de novo atrial fibrillation or bleeding, and prehabilitation based on exercise training, respiratory physiotherapy and nutritional and cognitive therapy, especially in fragile patients, stand out. There have been great advances, during the intraoperative phase, such as minimally invasive surgery, improved myocardial preservation, enhanced systemic perfusion and brain protection during extracorporeal circulation, or implementation of Safe Surgery protocols. Postoperative care should include goal-directed hemodynamic theraphy, a correct approach to coagulation disorders, and a multimodal analgesic protocol to facilitate early extubation and mobilization. Finally, optimal management of postoperative complications is key, including arrhythmias, vasoplegia, bleeding, and myocardial stunning that can lead to low cardiac output syndrome or, in extreme cases, cardiogenic shock. This global approach and the high degree of complexity require highly specialised units where intensive care specialists add value and are key to obtain more effective and efficient clinical results.

Early Versus Delayed Pacemaker for Heart Block After Valve Surgery: A Cost-Effectiveness Analysis

BACKGROUND

A significant percentage of patients who acutely develop high-grade atrioventricular block after valve surgery will ultimately recover, yet the ability to predict recovery is limited. The purpose of this analysis was to evaluate the cost-effectiveness of two different management strategies for the timing of permanent pacemaker implantation for new heart block after valve surgery.

METHODS

A cost-effectiveness model was developed using costs and probabilities of short- and long-term complications of pacemaker placement, short-term atrioventricular node recovery, intensive care unit stays, and long-term follow-up. We aggregated the total expected cost and utility of each option over a 20-y period. Quality-adjusted survival with a pacemaker was estimated from the literature and institutional patient-reported outcomes. Primary decision analysis was based on an expected recovery rate of 36.7% at 12 d with timing of pacemaker implantation: early placement (5 d) versus watchful waiting for 12 d.

RESULTS

A strategy of watchful waiting was more costly ($171,798 ± $45,695 versus $165,436 ± $52,923; P < 0.0001) but had a higher utility (9.05 ± 1.36 versus 8.55 ± 1.33 quality-adjusted life years; P < 0.0001) than an early pacemaker implantation strategy. The incremental cost-effectiveness ratio of watchful waiting was $12,724 per quality-adjusted life year. The results are sensitive to differences in quality-adjusted survival and rates of recovery of atrioventricular node function.

CONCLUSIONS

Watchful waiting for pacemaker insertion is a cost-effective management strategy compared with early placement for acute atrioventricular block after valve surgery. Although this is cost-effective from a population perspective, clinical risk scores predicting recovery will aid in personalized decision-making.

Predictors of pacemaker dependency in patients implanted with a pacemaker after Transaortic valve replacement

Introduction and objectives

The development of complete AV block and the need for pacemaker implantation (PM) is the most frequent complication after Transaortic valve replacement (TAVR). In other PM clinical contexts, a higher percentage of ventricular stimulation has been associated with worse prognosis. The objective was to study the existence of predictors of PM dependence.

Methods

We identified 96 consecutive patients who had received a PM post-TAVR (all Core-Valve). We retrospectively analyzed this cohort with the aim of identifying predictors of a high and very high percentage of ventricular pacing (VP), PM dependency and survival.

Results

The mean age was 82.3 years, with a mean logistic EuroSCORE of 17.1, 53% were women and 12% of patients had LVEF < 50%. The indication was complete AV block in 40.5%, and LBBB in 59.5%. Mean survival was 62.7 months, IQR [54.4-71]. The only independent predictor of mortality was the pre-TAVR logistic Euro-SCORE (RR = 1,026, p = 0.033), but not LVEF < 50%, VP > 50%, VP > 85% or PM dependence. In 73 patients PM rhythm was documented at the end of follow-up. Of these, 14 (19.2%) were considered dependent, and 37 (50.7%) presented VP > 50%. The post-TAVR complete AV block recovery rate was 67.8%. In multivariate analysis, female sex (HR = 5.6, p = 0.005), and indication of complete AV block vs. LBBB (HR = 15.7, p = 0.017) were independently associated with PM dependency.

Conclusions

Female sex and indication due to complete AV block were independent predictors of PM dependency during follow up. In our series of patients with mostly normal LVEF, a high percentage of stimulation does not influence prognosis.

[Surgical treatment of infective endocarditis: Surgical indications, complications, intrahospital and long-term mortality]

BACKGROUND

In addition to medical treatment, half of the patients with infective endocarditis (IE) receive surgical treatment. Despite clear recommendations on the indications and the operating delays, the decision remains difficult and must take into consideration several factors.

METHODS

A retrospective study was performed at Foch Hospital. All patients operated for IE between 2005 and 2018 were included. Patient characteristics, indications and operating delays, as well as intrahospital mortality, were noted. Patient follow-up was provided by phone calls.

RESULTS

Fifty-two patients were operated on for IE between 2005 and 2018. The most frequent surgical indications were the presence of a massive symptomatic regurgitation, an uncontrolled infection and large vegetations with embolism. The average operative delay was 13.2 days with 56.5% of patients operated within the first 10 days. The most common postoperative complications were acute kidney injury (AKI) in 57.7% of cases, with 9.6% of dialysis, shock in 50% of cases, rhythm disorders in 40.4% of cases, infectious complications in 19.2% of cases, conductive disorders in 25% of cases, of which 17.3% require a definitive pacemaker implementation. The intrahospital mortality was 7.7% and the average length of hospital stay was 35 days. Survival at one year and 5 years was 95% and 85%, respectively.

CONCLUSION

The indications and the operating delays were conformed to international recommendations. Intrahospital and long-term mortality rate was low.

Reduced Permanent Pacemaker Implantation in Patients With Stentless Freedom SOLO Compared With Stented Perimount Magna Aortic Bioprostheses: A Propensity Score Weighted Analysis

OBJECTIVES

Postoperative permanent pacemaker implantation (PPI) after conventional aortic valve replacement (AVR), due to new-onset severe conduction system disorders, is required in approximately 7% of patients. This study investigated the need for PPI after AVR with conventional stented Perimount Magna compared with the Freedom SOLO (FS) stentless valve (Sorin Group, Saluggia, Italy), now LivaNova plc (London, UK) that uses a strictly supra-annular, subcoronary running suture implantation technique, sparing the vulnerable interleaflet triangles in the region of the septum membranaceum.

METHODS

A total of 413 consecutive patients (71.4±9.2 yrs, 178 [43.1%] female) underwent isolated AVR using the stented Perimount Magna (n=264) or the stentless FS (n=149) bioprosthesis. Propensity score weighted analysis was used to account for patient-specific and procedural-specific variables, and to identify the prosthesis-specific need for early postoperative PPI within 30 days of AVR.

RESULTS

Twenty (20) patients required PPI, which was associated with longer intensive care unit (2.1±1.7 vs 1.5±3.0 days, p<0.001) and overall hospital stays (13.8±5.2 vs 10.7±5.3 days, p<0.001) compared with no PPI. Propensity weighted logistic regression including cross-clamp times identified that use of the stented Perimount Magna was associated with increased need for PPI, as compared with the FS, with an odds ratio 5.8 (95% CI, 1.09-30.76; p=0.039).

CONCLUSIONS

After corrections for all plausible confounders, AVR with the stented Perimount valve was associated with an odds ratio of almost 6 for an increased early postoperative need for pacemaker implantation compared with the FS stentless valve. This finding can be explained by the conventional implantation technique, which is potentially associated with mechanical trauma to the conducting system.

Permanent pacemaker implantation after cardiac surgery: Optimization of the decision making process

BACKGROUND

Conduction disturbances necessitating permanent pacemaker (PPM) implantation after cardiac surgery occur in 1% to 5% of patients. Previous studies have reported a low rate of late PPM dependency, but there is lack of evidence that it might be related to implantation timing. In this study, we sought to determine whether PPM implantation timing and specific conduction disturbances as indications for PPM implantation are associated with late pacemaker dependency and recovery of atrioventricular (AV) conduction.

METHODS

Patients with a PPM implanted after cardiac surgery were followed in an outpatient clinic. Two outcomes were assessed: AV conduction recovery and PPM dependency, defined as the absence of intrinsic rhythm on sensing test in VVI mode at 40 bpm.

RESULTS

Of 15,092 patients operated between September 2008 and March 2019, 185 (1.2%) underwent PPM implantation. One hundred seventy-seven of these patients met the criteria for inclusion into this study. Follow-up data were available in 145 patients (82%). Implantation was performed at ≤6 days after surgery in 58 patients (40%) and at >6 days after surgery in 87 patients (60%). The median time from implantation to last follow-up was 890 days (range, 416-1998 days). At follow-up, 81 (56%) patients were not PPM dependent. Multivariable analysis showed that PPM implantation at ≤6 days after surgery is a predictor of being not PPM dependent (odds ratio [OR], 5.40; 95% confidence interval [CI], 2.43-12.04; P < .001) and of AV conduction recovery (OR, 4.96; 95% CI, 2.26-10.91; P < .001). Sinus node dysfunction as indication for PPM implantation was predictive of being not PPM dependent (OR, 6.59; 95% CI, 1.67-26.06; P = .007).

CONCLUSIONS

We recommend implanting a PPM on postoperative day 7 to prevent unnecessary implantations and avoid prolonged hospitalization.

Incidence of permanent pacemaker implantation after valve replacement surgery : Cardiac structure and function at 1-year follow-up

BACKGROUND

Our study aimed to explore the incidence and risk factors of permanent pacemaker implantation (PPI) after valve replacement surgery (VR). The influence of long-term pacemaker dependency on cardiac structure and function at the 1‑year follow-up was also assessed.

METHODS

The demographic and surgical data of all consecutive patients who underwent VR between 2013 and 2016 were collected. Univariate and multivariate analyses were performed to identify variables independently associated with PPI after VR. A 1‑year follow-up was undertaken of patients who underwent dual-chambers pacemaker after VR because of complete atrioventricular block (AVB). Long-term pacemaker dependency and recovery of cardiac structure and function were evaluated.

RESULTS

There were 5320 consecutive patients with VR. The incidence of postoperative PPI was 2.42%. Multivariate analysis indicated that among the 62 patients who underwent PPI due to AVB and sick sinus syndrome, isolated aortic valve replacement (AVR; OR: 2.24, p < 0.05), VR combined with ventricular septal defect (VSD) repair (OR: 6.78, p < 0.05), and VR with aortic root and arch surgery (OR: 4.14, p < 0.05) were independent predictors of PPI after surgery. In total, 89.6% (43/48) of the survivors showed pacemaker dependency. Of these 43 patients, 24 had enlarged left heart before VR. Compared with preoperative values, the left atrial and left ventricular end-diastolic diameter post-PPI decreased significantly, while left ventricular ejection fraction was not significantly different.

CONCLUSION

Isolated AVR, VR concomitant with VSD repair, and VR with aortic root and arch surgery are independent predictors of PPI after VR. The majority of patients do not recover from AVB disorders and there is no significant negative effect on recovery of cardiac structure and function.

Incidence of Atrioventricular Block After Valve Replacement in Carcinoid Heart Disease

Background

Carcinoid heart disease (CaHD) is a rare condition that has a high impact on the morbidity and mortality of its patients. Once heart failure symptoms develop in the patient with CaHD, cardiac valve surgery is often the only effective treatment. Although atrioventricular block (AVB) is a known postoperative complication of the valve surgery, the incidence of AVB in this population has not been well described.

Methods

Comprehensive records were collected retrospectively on consecutive patients with CaHD who underwent a valve surgery at a tertiary medical center from January 2001 to December 2015. We excluded patients with pre-existing permanent pacemaker (PPM).

Results

Nineteen consecutive patients were included in this study and 18 of them underwent at least dual valve (tricuspid and pulmonary valve) replacement surgery. Our 30-day post-surgical mortality was 0%. During the 6-month observation period following the surgery, 31.5% (n = 6) required PPM implantation due to complete AVB. There was no statistical difference in baseline characteristics and electrocardiographic and echocardiographic parameters between the patients who did or did not require PPM placement.

Conclusions

Our study revealed that almost one-third of CaHD patients who underwent a valve replacement surgery developed AVB requiring PPM implantation. Due to high incidence of PPM requirement, we believe that prophylactic placement of an epicardial lead during the valve surgery can be helpful in these patients to reduce serious complication from placement of pacemaker lead on a later date through a prosthetic valve.

Frequency of Recovery from Complete Atrioventricular Block After Cardiac Surgery

Best timing for permanent pacemaker implantation to treat complete atrioventricular block (AVB) after cardiac surgery is unclear, as late pacemaker dependency was found low in recent observational studies. This study aimed to identify factors associated with spontaneous recovery from AVB. In a prospective and observational cohort, all patients who underwent cardiothoracic surgery during a 14-month-period were included (n = 1,200). Risk factors of postoperative AVB were assessed by logistic regression. Among patients who developed AVB, variables associated with recovery from AVB were assessed by Cox and logistic regression. Overall incidence of postoperative AVB was 6.0%. Risk factors of AVB were age (OR 1.03 [1.00 to 1.06], p = 0.023); female gender (OR 2.06 [1.24 to 3.41], p = 0.005), active endocarditis (OR 3.31 [1.33 to 8.26], p = 0.01), and aortic valve replacement (OR 3.17 [1.92 to 5.25], p <0.001). Among aortic valve replacement, sutureless aortic valve replacement was associated with more AVB (26.7% vs 8.1%, p <0.01). Recovery from AVB occurred in 30 patients (41.7%) in a median period of 3 days [interquartile range = 1;5]. Among patients who would recover from AVB, 90% of patients did so before day 7. None of the studied variable was independently associated with recovery from AVB. In conclusion, identified risk factors of postoperative AVB after cardiac surgery were age, female gender, endocarditis, and aortic valve replacement. Because most patients who would recover did so before day 7, this study validates modern guidelines suggesting permanent pacemaker implantation on day 7.

Low pacemaker incidence with continuous-sutured valves: a retrospective analysis

Background Permanent pacemaker implantation after surgical aortic valve replacement depends on patient selection and risk factors for conduction disorders. We aimed to identify risk criteria and obtain a selected group comparable to patients assigned to transcatheter aortic valve implantation. Methods Isolated sutured aortic valve replacements in 994 patients treated from 2007 to 2015 were reviewed. Demographics, hospital stay, preexisting conduction disorders, surgical technique, and etiology in patients with and without permanent pacemaker implantation were compared. Reported outcomes after transcatheter aortic valve implantation were compared with those of a subgroup including only degenerative valve disease and first redo. Results The incidence of permanent pacemaker implantation was 2.9%. Longer hospital stay ( p = 0.01), preexisting rhythm disorders ( p < 0.001), complex prosthetic endocarditis ( p = 0.01), and complex redo ( p < 0.001) were associated with permanent pacemaker implantation. Although prostheses were sutured with continuous monofilament in the majority of cases (86%), interrupted pledgetted sutures were used more often in the pacemaker group ( p = 0.002). In the subgroup analysis, the incidence of permanent pacemaker implantation was 2%; preexisting rhythm disorders and the suture technique were still major risk factors. Conclusion Permanent pacemaker implantation depends on etiology, preexisting rhythm disorders, and suture technique, and the 2% incidence compares favorably with the reported 5- to 10-fold higher incidence after transcatheter aortic valve implantation. Cost analysis should take this into account. Often dismissed as minor complication, permanent pacemaker implantation increases the risks of endocarditis, impaired myocardial recovery, and higher mortality if associated with prosthesis regurgitation.

Pacemaker Dependency after Cardiac Surgery: A Systematic Review of Current Evidence

Background

Severe postoperative conduction disturbances requiring permanent pacemaker implantation frequently occur following cardiac surgery. Little is known about the long-term pacing requirements and risk factors for pacemaker dependency in this population.

Methods

We performed a systematic review of the literature addressing rates and predictors of pacemaker dependency in patients requiring permanent pacemaker implantation after cardiac surgery. Using a comprehensive search of the Medline, Web of Science and EMBASE databases, studies were selected for review based on predetermined inclusion and exclusion criteria.

Results

A total of 8 studies addressing the endpoint of pacemaker-dependency were identified, while 3 studies were found that addressed the recovery of atrioventricular (AV) conduction endpoint. There were 10 unique studies with a total of 780 patients. Mean follow-up ranged from 6–72 months. Pacemaker dependency rates ranged from 32%-91% and recovery of AV conduction ranged from 16%-42%. There was significant heterogeneity with respect to the definition of pacemaker dependency. Several patient and procedure-specific variables were found to be independently associated with pacemaker dependency, but these were not consistent between studies.

Conclusions

Pacemaker dependency following cardiac surgery occurs with variable frequency. While individual studies have identified various perioperative risk factors for pacemaker dependency and non-resolution of AV conduction disease, results have been inconsistent. Well-conducted studies using a uniform definition of pacemaker dependency might identify patients who will benefit most from early permanent pacemaker implantation after cardiac surgery.

[Atrioventricular block after cardiac surgery: report of 23 cases]

Le bloc auriculo-ventriculaire (BAV) représente une complication non négligeable de la chirurgie cardiaque. Il est responsable de séquelles lourdes et graves compromettant le pronostic de la maladie et conduisant à la mise en place d'un stimulateur cardiaque définitif. Il est primordial d’étudier et de déterminer les différents facteurs prédictifs de BAV post opératoire, son histoire naturelle, son incidence ainsi que le délai exact de la mise en place d'un pacemaker. Notre étude est une étude rétrospective descriptive à propos de 23 patients opérés pour chirurgie cardiaque sous circulation extracorporelle entre octobre 1989 et août 2010 ayant présentés des troubles conductifs auriculo-ventriculaires en post opératoire. Plusieurs facteurs de risque ont été étudiés dans notre série, liés surtout à l'atteinte directe du noeud auriculo-ventriculaire ou à l'ischémie myocardique. Le délai d'apparition du trouble conductif ainsi que le délai d'implantation on été également étudié. Plusieurs facteurs favorisants de survenue de BAV ont été identifiés liés essentiellement au type de la cardiopathie opérée avec une prédominance de la cardiopathie congénitale, d'autres facteurs ont été rapportés notamment la présence d'hypertrophie ventriculaire gauche (HVG) de troubles conductifs en préopératoire, une durée du clampage aortique et de CEC prolongée. La moitié des patients ont présenté un BAV immédiat. Le délai d'implantation par rapport à la date de la découverte du BAV varie dans notre série d'une implantation immédiate après le diagnostic positif (J0) à un délai d'implantation allant jusqu’à 57 jours. Plusieurs facteurs de risques déterminent la survenue de BAV post chirurgie cardiaque, leur connaissance est primordial ainsi que le délai exact de l'implantation du stimulateur cardiaque définitif.

Pacemaker dependency after isolated aortic valve replacement: do conductance disorders recover over time?

OBJECTIVES

Permanent pacemaker (PPM) implantation is required in 3-8% of all patients undergoing aortic valve replacement (AVR). Our aim was to evaluate long-term PPM dependency and recovery of atrioventricular (AV) conduction disorders during follow-up in these patients.

METHODS

Since January 1997, a total of 2106 consecutive patients underwent isolated AVR at our institution. Of these, 138 patients (6.6%, 72 female, median age 71 (37-89) years) developed significant conduction disorders leading to PPM implantation postoperatively. Preoperative ECG showed normal sinus rhythm (n = 64), first degree AV block (n = 19), left bundle branch block (n = 13), right bundle branch block (n = 16), left anterior hemiblock (n = 14) and AV block with ventricular escape rhythm (n = 10). Atrial fibrillation was present in 23 patients. Pacemakers were implanted after a median of 7 (1-30) days following AVR. PPM dependency was analysed by ECG and pacemaker check during follow-up.

RESULTS

A total of 45 of 138 patients with postoperative PPM Implantation died during a mean follow-up time of 5.3 ± 4.7 years. A further 9 patients were lost to follow-up. Long-term survivals at 1, 5 and 10 years were 88%, 79% and 59%, respectively. Only 8 (10%) of 84 survivors were no longer pacemaker-dependent. The majority of patients (n = 66, 79%) required permanent ventricular stimulation, and the remaining 10 (13%) showed intermittent stimulation with a mean ventricular stimulation fraction of 73% (22-98%).

CONCLUSIONS

The majority of patients do not recover from AV conduction disorders after AVR. Since higher-grade AV blocks expose patients to a high risk of sudden death after surgery, we recommend early implantation of permanent pacemaker.

Arrhythmias in the coronary care unit

Symptomatic sustained cardiac arrhythmias are frequently observed in in the coronary care unit and often lead to hemodynamic compromise, especially in the presence of multisystem disease. The predominant arrhythmias noted in intensive care units are tachyarrhythmias, particularly atrial fibrillation and flutter, and ventricular tachycardia. Bradycardias, arguably less life-threatening than tachyarrhythmias, can arise from sinus node dysfunction or atrioventricular conduction block; transient vagally-mediated bradycardias are frequently encountered as well. Prompt diagnosis of the patient with tachycardia is critical as treatment depends on the accurate diagnosis of tachycardia mechanism. The electrocardiogram remains the most important diagnostic tool for the evaluation of both wide and narrow complex tachycardia. The electrocardiographic diagnosis of wide complex tachycardia is based on evaluation of atrioventricular relationship and QRS morphology while the diagnosis of narrow complex tachycardia is based on the location and morphology of P waves. It is important for critical care specialists to understand the principles of cardiac arrhythmia diagnosis and remain current with the recent advances in the pharmacologic and non-pharmacologic management of patients with arrhythmias.

Early and delayed atrioventricular conduction block after routine surgery for congenital heart disease

OBJECTIVES

Patients undergoing surgical closure of ventricular septal defects are at risk for immediate or delayed atrioventricular conduction block. Our goal was to better define the incidence of delayed atrioventricular conduction block.

METHODS

A retrospective review was conducted of hospital records and pacemaker database for ventricular septal defect, atrioventricular canal, and tetralogy of Fallot repairs between 1999 and 2004. A total of 922 patients were identified (atrioventricular canal in 197, tetralogy of Fallot in 222, and ventricular septal defect in 503). Median follow-up was 4.1 years.

RESULTS

There were 472 male and 450 female patients, median age 6 months (0-444 months) and median weight 5.8 kg (1.3-116 kg) at surgery. Postoperative atrioventricular conduction block developed in 21 (2.3%) of the 922, being transient, with return of conduction 3 days (1-14 days) after surgery, in 13 (1.4%) and permanent, with pacemakers implanted 10 days (6-20 days) after surgery, in 8 (0.9%). Of the 905 patients at risk for delayed atrioventricular conduction block, 3 (0.3%) had second- or third-degree block at 2, 8, and 16 months after surgery. Two of these 3 had transient postoperative block. For isolated ventricular septal defects, the incidence was 1 (0.2%) of 496. There were 8 late deaths at 31 months (7-45 months) after surgery. Five had normal conduction at death, but for 3 patients the conduction status at death could not be determined. Including these 3 patients as possible cases of delayed atrioventricular block yields an incidence of 0.3% to 0.7%.

CONCLUSIONS

The incidence of early atrioventricular conduction block requiring a pacemaker was 0.9% and that of delayed atrioventricular conduction block was 0.3% to 0.7%. Transient atrioventricular conduction block may be a marker for increased risk of delayed block. These data may be useful for evaluation of new techniques.